Physical Exam

Right sided valves open earlier due to lower pressure gradient in right sided chambers.

Right sided valves

Closure of mitral and tricuspid valves

Closure of aortic and pulmonary valves

P2. It is a right sided valve and therefore closes later.

During inspiration, there is an augmentation in venous return, which results in a delay in the closure of the right sided valves. Tricuspid valve is delayed, but this is not appreciable on bedside exam.The closure of the pulmonic valve is delayed by 40-60msec is heard as splitting of the 2^nd heart sound.

Persistent splitting

• RBBB
• Pulmonary HTN

Fixed Splitting

• ASD

Paradoxical splitting

• LBBB (electrical cause)
• RV pacing (electrical cause)
• LV systolic failure (mechanical cause)
• AS (mechanical cause)
• HOCM (mechanical cause)

Persistent splitting

There is delay in the activation of the RV.Even with expiration, the pulmonary component of S2 is delayed and there is persistent splitting.

Fixed splitting

The P2 component of S2 is significantly delayed, even in expiration.This is due to increased flow from the left atrium to the right atrium and ultimately through the right sided chambers. This increased flow through the right sided chambers results in delay of P2 during expiration.During inspiration, there is augmented venous return to the right chambers causing the expected delay in P2. This also results in decreased flow through the shunt and P2 occurs at an equally delayed time resulting in fixed splitting of S2.

Paradoxical splitting of S2

LBBB/RV pacing results in electrical delayed activation of the LV. This results in delayed closure of the AV.The P2 component of S2 occurs before A2. During inspiration, the P2 component is delayed and temporally moves closer to the already delayed A2. P2 and A2 occur at the same time.

There is delayed left ventricular outflow.

Pulmonary HTN